Early identification of children with FASD has been limited by the difficulty of reliably evaluating facial dysmorphology and because investigators have not yet identified a set of neurobehavioral deficits specifically related to prenatal alcohol exposure. However, a new generation of neurodevelopmental measures that have been linked more specifically to neural processes and pathways has the potential to improve FASD diagnosis. We have recently completed a prospective study of 159 infants born to mothers from the Cape Coloured (mixed race) community in South Africa, which has confimed the exceptionally high incidence of maternal alcohol abuse and dependence and FAS previously documented in this population. Arithmetic and executive function (EF) are among the most consistently affected domains in older children with FASD. In our Cape Town cohort, we were able to detect deficits in these domains in infancy using two innovative infant assessments: a numerosity test, which assesses magnitude representation, a precursor of arithmetic that has been linked to inferior parietal function, and the A-not-B test, an early precursor of EF. New data from our Detroit prenatal alcohol exposure cohort also provide evidence of a specific deficit in magnitude representation in older children and poorer conflict monitoring, an aspect of EF believed to be mediated by the anterior cingulate cortex. This component of the Collaborative Initiative on Fetal Alcohol Spectrum Disorders (CIFASD) will follow up our Cape Town cohort at 4 and 6 years of age. The specific aims are: (1) to administer new narrowband tests of arithmetic and EF to determine which elements of these domains appear to be core deficits of FASD; (2) to administer event-related potential (ERP) assessments of magnitude representation and recognition of facial emotional expression, two domains that are hypothesized to relate specifically to FASD; (3) to test the hypothesis that two moderator variables---maternal age and the absence of an ADH2*2 allele--can improve the identification of FASD in prenatally exposed children; (4) to assess the predictive validity of infant numerosity and A-not-B in relation to cognition and attention in early childhood; (5) to determine the degree to which measures of craniofacial variation derived from 3-D photography can improve FASD diagnosis; and (6) to administer additional neurobehavioral assessments in common with other CIFASD projects to provide data on the sequelae of FASD that can be pooled and compared across age, site and ethnic group. Improvement of diagnosis in infancy and early childhood and a better understanding of the specific domains of neurobehavioral function affected by fetal alcohol exposure are critically important for the development and implementation of targeted, effective interventions for FASD.